1. Field of the Invention
The present invention relates to optical focusing, and more particularly to loading and unloading a flying lens used for optical data storage.
2. Background of the Invention
The use of optical data storage disks is known in the art. Examples include compact disks (CDs), magneto-optical disks (M/O), and digital video disks (DVD). Recently it has been proposed that systems using multiple lenses, including a "flying lens," be used to increase the storage capacity of the optical data storage disks. Such flying lenses are maintained at a nearly fixed distance from the surface of the rotating disks by aerodynamic effects.
The use of flying heads for use with magnetic data storage disks is known in the art, although they differ somewhat from flying lenses. A flying lens is a lens in an optical system and it may cooperate with one or more other lenses, such as a moveable objective lens. A flying lens optical system can be used with both fixed and removable storage media. All lenses in the optical system must maintain alignment with each other and a light source. This alignment requirement is absent in flying heads used for magnetic data storage systems. In addition, a flying lens assembly is typically larger in size than a flying head.
Many known prior art optical storage systems do not use a flying lens and thus do not require rotation of a disk, and the associated aerodynamic effects, to keep lenses separated from the surface of the storage media. The lens position in these systems is away from the surface of the optical storage media. These prior art systems do not require "unloading" the lens from the surface of the storage media before stopping disk rotation. Flying lens optical systems have been proposed and discussed in the literature. Such filing len systems do require a method or apparatus for loading and/or unloading these flying lenses.
Known prior art magnetic data storage systems which use flying heads often require such unloading. However, the heads are much smaller and there is no need to maintain the critical optical alignments as with components of optical data storage systems.
A technique known in the art and sometimes used with flying head magnetic systems is to "park" the head against the surface of the storage media. This parking may be done on a rough surface to minimize adhesion between the parked head and the magnetic disk surface. The surfaces of optical data storage disks however typically lack such rough surfaces and the larger physical size of a flying lens assembly increases the adhesion. These traits increase the likelihood of damage to flying lens optical systems which park the flying lens on the disk surface compared to flying head magnetic systems.
Accordingly, it would be desirable to provide a system to load and unload a flying lens used with optical data storage disks.